Multiple motor



March 30, 1948. A. R. STONE MULTIPLE MOTOR 5 Sheets-Sheet 1 Filed June22, 1945 i INVENTOR. ALBERT RlvlNGToN. STONE @zou HIS ATTORNEY TUT@March 30, 1948. A. R. STONE 2,438,686

MULTIPLE MOTOR Filed June 22, 1945 3 Sheets-Sheet 2 v59 5e 2B I ALBERTRIVINGTON STONE HIS March 30, 1948. A R, STONE 2,438,686

MULTIPLE MOTOR Filed June 22, 1945 5 Sheets-Sheet 3 LH 3 ALBERTRlvnNGTON STONE Patented Mar. 3 0, 1948 UNITED STATES PATENT OFFICEMULTIPLE MOTOR Albert Rivington Stone, Baltimore, Md.

Application June 22, 1945, Serial No. 600,947

2 Claims. 1

My invention relates to hydraulic power units and as Well, to a novelassembly and control means therefor, for braking a hydraulic or othertype motor unit.

A manually-actuated type of control unit for regulating an assembly ofthe general type described is disclosed in my companion application,Serial No. 594,279, filed May 1'7, 1945, and entitled Hydraulic system.This unit can be effectively included in my new assembly with entirelysatisfactory results, the resulting assembly being either manually orautomatically controlled as the case may be.

One object of my invention is to provide a variable speed motor havingassociated therewith means for holding it against motion in simple,positive, and efiicient manner, together with means operable as desiredfor quickly and sensitively releasing said holding means, both theholding and releasing means comprising simple, sturdy and durableelements, inexpensive in themselves and involving a minimum number ofmoving parts, and which, displaying high reliability and sensitivity inoperation, require but a minimum of trained supervision.

Another object is to provide a power unit including a motor -of the typedescribed in which I combine paired flruid motors for energizing a.common power take-ofi shaft, the rst said motor normally beingeffectively restrained from contributing to the drive of said take-offshaft, and its effect being compounded, when desired, on the drive shaftin simple, direct and eicient manner, and with but minimum requirementof intermediate mechanisms and these of simple, sturdy and comparativelyinexpensive construction, the power unit itself displaying theadvantageous qualities of ruggedness, long life', and low wear.

Still another object is to provide a power assembly embodying a powerunit of the general type described in which the latter is energized, insimple, reliable and dependable manner, and with maximum efficiency anda minimum of first investment, from a common source of fixed output,unidirectional fluid energy, the assembly embodying an intermediatecontrol unit which effectively and sensitively, under either manual orautomatic control, determines the exact part of the constant output ofthe energy source which courses to a particular motor, and as well, thedirection in which that motor is energized. This assembly ischaracterized by its simplicity, compactness and unitary, self-containedconstruction, its small number of moving parts, and

its consequent low cost both of construction and in subsequent operationand maintenance.

Other objects will in part be obvious and in part pointed outhereinafter during the course of the following description.

My invention accordingly resides in the several parts, elements, andfeatures of construction, as well as in the mode of carrying them intoexecution, in the several operational steps, and in the combination ofeach of the same with one or :more of the others, thescope of theapplication of all of which is more fully set forth in the claims at theend of this specification.

Referring now more particularly to the drawings, wherein I illustrate,one embodiment of my invention which I prefer at present,

Figure 1 comprises a schematic view of the complete assembly;

Figure 2 is a vertical longitudinal section through a power unitembodying my new braking means taken on the lin-e 2 2 of Figure 4, andlooking in the direction of the arrows;

Figure 3 is a transverse vertical section taken on the line 3-3 ofFigure 2 and looking in the direction of the arrows; while,

Figure 4 is an end View taken at the left end of the unit of Figure 2.

As conducive to a more thorough understanding of my invention, it isadvantageous at this point to consider briefly the development of fliuidpowering systems, so far as they aff-ect the evolution of my new powerassembly.

The high, degree of flexibility of hydraulic powering means effectivelyensured the widespread acceptance of such units even when they wereiirst introduced into the industrial arts. Particularly whenmulti-chambered rotary pumps and motors were evolved, permitting smooth,continuous power impulse to loads having both high torque and speeddemands, widescale acceptance was quickly achieved. The exiblecharacteristics of hydraulic equipment resulted in many economies whichhad not been possible with powering equipment theretofore available. Toillustrate, it became entirely practicable to adapt a single machine fora number of different services, each of somewhat diverse loadrequirements and characteristics, such as varying rotational speed,varying torque demands, etc. Thus, a single piece of equipment could beadvantageously and effectively adapted in rapid, simple, and economicalmanner for servicing loads of widely divergent type, provided only thateach such load was substantially constant and of substantially unvaryingdemand.

Voverhead and depreciation charges.

When, however, it became necessary to service loads of rapidlyfluctuating and Varying demand, both as to torque and speedrequirements, substantial diiiiculties were still encountered, despitethe increased ilexibility inherent in hydraulic powering equipment. Toemploy several power units of like or dissimilar ratings, any one ormore of which were brought onto the line as required to handlethezloadatmaximum unit eiliciencies during quiet or sub-normal conditions, other4units being brought into operation when `n orrnal or peak loadconditions maintained, s would dissipatevin substantial measure thewad-fV vantages attendant upon the use `of hydraulic equipment despitethe highly iiexiblacharac'ter istics of the latter. x necessarilyinvolved, with attendant increase in tages of flexibility within`4 thepower unit were surrenderedf- Moreoverfarater plant Sptere.- Y

quirements ere., ,inyvolx/ged,r and either skilledSupervisiim'Wasneessarm 0r expensive automatic auxiliaries-wereinvolved,A Either recourserep- Substantial ',rst costyvas.

The advan- Y. l

resented a still further increase ,in both space rearmements-andplantinvestmena A vfurther; nexpedient,:similarly impracticable,Wasctegzemploy a. singlelunitcf. substantial power ratingwhich@COuIdSQDerate-,either at'under-load for normal orl oft-peakintervals and at full maxe,v imum lcutput; for; peakgloadrconditions, orelse,

could,begdesignedfforgoperation vat. rated normal output for quiet,subnormal. or off-peak periods and-under,overloadfcauditionsfor peakload clemands.1:.In.the..-rstz-instancelthe advantages ofV c iluidequipment iweuld be. materially sacriced in that,.thenormalgnfffloadoperation v.would be, `at

materially reduced efficiency, thussurrendering. the -advanta'gebflhighsystemeiciency which comprisessanotheri. and `;highly important, featureof advantage'ohliydraulic-equipment.. Onlyat. peak loadconditions,ordinarilyinvolving.but a. small-'portionpi the;dai1yoperation Vwouidnish.- efficiencies :berapproximated. .On the-other.hand,

with the second embodimentzwherein.,highyle'f CienCesg ara;observed-during normal operati-on,... therdanger is alwayspresentthatuponpeak load condition,V u,endurance of such; conditions;Veither at extremelyyhehxdemand i017;short.periods..ofv tmcrr;kGQiltinuedf,peakpdemandY ,over an unex-y Dledly; extended period-4 ,ofYtime, might result` in serious damage ,prfevenL destructionof thepervert-unit.; In many'types, .of .uuidequipment,A

this-Would be manifestedeiniluid leakage losses ,l of such seriousectthat v.the systemwouldfstall. v

Non-stall serve AD ioreriis to, remove and, eliminate lrin,substantialcharacteristics would no longer be yob,-

:measure theseveral disadvantages and defects of g the. s3. fs`te m. s vheretofore available; all as hasbeen moreyfully set orthhereinbefore,and at .the same Y v tima-togv achieve a new p-ower unit. involvingmul-H tiplellliors, in which ,one or more of the motors f iseiectivelyrestrained agfinstgmotion at all times;whenvitstaande-energized, and to releasefthe;samequickly, reliably, andeiciently when fluid @Gravis ,applied thereto.toV brins the motorY intooperation. K It iS-IHY further object to accomplish all Vthisin simple,direct and efcient manner Y ,th a-. minimum complexity ofauxiliaryequipmentaatlow-'first ,costand low requirements of maintenanceandsupervision. -Astill Yfurther abject istoksrovidefamotr unit ofthc-@general tvp@ deseaban,fineeraoratins'braking means of Vthe generaltype'just referred to; Y

i -Y Mctolifltis' design darid 4 p Now having attention moreparticularly to the embodiment disclosed in the several views of thedrawings, discussion will first be had of the system as a whole, then ofthe motor and power take-oir assembly, including the brake for what isknown as the slewing motor, which will later bedescribed, and then ofthe control unit itself. In this manner,A a Vmore comprehensiveyunderstanding mayIv lbehad of the precise constructiona'ldetails';

-Basically (having reference t-o Figure 1), the system comprises aconstant speed, constant output, and.; unidirectional source ofhydraulic power I0, paired hydraulic motors indicated generally attI-,aicontrolrunit indicated generally at I2, abrake,controlqunitindicated generally at I3, and a fluid reservoir |47',all included in what may b-e termeda closed hydraulic circuit.

More specically, the pump I0 generates a1- waysat maximurngeiciency,delivering, reaardfj` lessofgthe variation. of: load onfthe vpairedmotorV unit I |.or.\vhetherone `orbe-th of saidmotor's is 1V energizedat any particular time, a cocrJStant onta` put of constantsreed andwhicnis deliveredfm but,V asingle direction. -I Vpr,efe r t o useafnollf'ff pulsating-type; 0i iiuid pump, Ywhich...necessarilyI fsubstantially restricts theselection; tnlthe rotary: type 'of pump.Inasrnuch, as operatonis .desredL-v.V Y Y Aagainst all ranges* of,pressure Yheads including;-

those of substantiai..` value, .IpreferftnremplQy -arotary A pumpgor lthev multi. chambered typen wherein the separate pumpingfefortsof-thein' dividualchambers,are'cascadedgoneOnthefother;

so tiiatthe sum...tata1;0f"the pumpineeiiortisioi,

substantial magnitude Anyrembodiment offthisz type @trump ai.

'paired` fluid motorsof unlike,- characteristics.`

Theiigniiicantpointin this connection is that the.motorassemblrmavbesubstantiallvrtailolefi: e to adapt; it bestfQrtheeeneralranee of hydraulic 'l asignada In the-inf. Y stance heresmderense-destriptenf asl i Y true `-ofthe' speci'iic embodimentsdescribed in my i said two @tendina appliatiens,-;these metersA 1,51

problemsVV for, -whichit and I6 are intended; oroperatineiaiturretpctzri trol Offanvseneraiftypei ',rlartipullarlr, Vhvvev it isf designedgfor efctivefr'oneratirr or ther-su turret of landtanks and similar vehicles.

plish.. rapid startin motor ,f .@Ollples bigv motionrthef effect. 'olfVmotor IG is compounded 0n that 0f motoll high-speeddut'y. This quicklyswings the tur-.f

isciosedfn ithez Copending- Bartholomew-- F .-Qu11ltilian application,vSerial gNogg'; 535,033; led .Mayall-,1944; and;enti-tiemarly-r1y drauliCpump. andmotony-z Itis-entirely possilola: however, to.k incormratesuccessfullr in, new assembly c any suitable., conventional and f,avail-A ablegrtypeY of., rotary hydraulic; pump capable'r of operatingragainstsubstantial` lJlessure heads..r

l The paired;.mctcrassemblylrmayrconsst of like :Huid: ,metershavinafsimilar; Characteristics or ,riminiA asinsthelpresentfinstancecomprise;

retthrough its travel. andwbringsthegun approximately4 on'its target. Atthis pointrit is important to takethe` motor JII quickly out vofoperation and, underthecontrol-of .motor I5, overcome the :inertiaofmotionvof-thetank turret, andi tocornplete inquickandaccurate nannervthe training ofthe gunon its target without any hunting of the motors.

Thesemotors -I5.-and -lfinasmuch as they operate against substantiallyheavy-duty load conditions, arelbothpreferablyof the high-pressuretype.For-effective lutilization of the nonpulsatingenergizingfluid'fromA pumpIll, fluid motors I'5,I5 are preferably ofthe rotary type. Moreover,high-pressure duty dictates that they be of the multi-chambered variety.It is entirely possible, however, to use any suitable type of variable-direction, multi-chambered lrotary fluid motors. Like satisfactoryresults can be achieved by such-use.

The motors I andv I6 are schematically illustrated in Figure 1 asmounted on a common body Il. This is simply a schematic representationof a self-contained unitary mounting on a suitable foundation,suliciently rugged to withstand all vibrational disturbance and torquereaction.

As has been stated, pump Il and motor unit II are connected through whatmay be termed a closed hydraulic circuit which includes the reservoir I4 and control unit I2, the braking control I3 constituting an auxiliarybranched from the main hydraulic-circuit, in the nature of a bleederline. Reservoir I4 effectively serves to ensure that at Aall timessufficient fluid is available in the system to compensate for leakagelosses, etc.

It has been stated that. pump Ii) is of constant, uni-directionaloutput, while motors I5, I5 can be energized in desired manner from thepump I5. This is accomplished through control unit I2. Very briefly, thefunction of the control I2, is either under manual or automaticregulation, here shown asmanual, Vto handle the full output of pump Iand to direct it through the proper channelsI and in proper`proportions, either rst, directly back as by short-circuit to reservoiri4; second, to motor I5; third, to motor le; fourth, to motorsi I5 andI5, in any desired combination, in any desired proportions, and indesired `directions so far as concerns motors I5 and I6.

Toaccomplish the energization of motor I5 or I5, or both, in desireddirections four-way valves I8 and I9 are included in the control uniti2. Auxiliary control I3 is physically included in the control unit I`2,and is operated from the control shaft 20, which is common to the twocontrol elements and is shown as operable manually through aconventionally-illustrated handle 2|. Before directing further attentionto control unit E2, however, attention will now be directed to the powerunit or motor assembly shown in Figures 2 through 4, inclusive.

The tracking motor, of high torque, low-speed characteristics,is'indicated generally at I5 in TFigure 2, having ports 23, 24 (Figures1 and 4) which are interchangeably available as inlet and outlet ports,respectively, depending uponv the direction in which motor 22 isenergized. The desired torque Aand speed characteristics are achievedthrough the gearing by which motor '22 (corresponding to motor I5 ofFigure 1) powers take-off shaft 25 (Figure 2). For convenience ofassembly, the motor 22 is contained in a multiple housing, comprising,generally end plate.526,-intermediate motor lblo'ck .2 'I, a larger unitblock 28 and a furtherend plateZS. Motor-22 is carried in-block` 21 insruitable antifrictionfmanner `as byvneedle bearings 30. Itis made fastto shaft 43| inv suitable manner asby key 32.

It will be noticedthat thestub shaft part of shaft SI which protrudeslto the left of tracking motor 22 is of' larger diameter and of shorterlength than-that portionthereof protruding to the right of motor 22.This left partofshaft 3| serves as a counterpoise for theworking end ofthe shaft, which protrudes to the right. Suitable antifrictionbearings,` such as needle bearings 33, serve to carry this'stub shaft 3lin end member 26. Sealing gasketv34, drainage means 35, and end cap 35serve to close the left terminal of the bore through end member-25.

Within block A28'is carried suitable bearing members such as ballbearings 3l iny lconcentric relation with' the needle bearings v38 whichdirectly carry shaitI. Betweenthe concentric bearings 3l,- 38 isprovided the annular hub 39, comprising a'sleeve like member, of ringgear spider 45. This spider-4D terminates in an axially-offset ringgear'4I having outer teeth 42 yand inner teeth 43. The inner teeth43mesh with the corresponding teeth of planet gears r44, a number of whichare rotatably carried in power take-off spider 45. Spider-45 is disposedat the 4right of ring gear lil `andplanet gears 44, in .a suitableannular space krlili provided by complemental openings in block28 andend member 25.

The extreme right end of shaf-t SI terminates in a tongue 35a ofgenerally rectangular section, snugly received in a recess "4l of nomplemental shape provided in a hub 49 of sun gear5il. lEnd plate 29carries a ball bearing 5I forreceiving in anti-friction manner the powertake-off shaft 25 which is fast to power-take-of spider 45 and whichserves to transmit the power rfrom the tracking and slewing motors to acommon load. Sealing gasket 53 serves effectively to prevent leakage tothe exterior past endplate 29. Effective use is made of a number ofsuitable anti-friction bearings, for securely protecting the severalparts of the drive mechanism from frictional wear :against each other,resulting from either rolling contact or end play.

Depending upon the manner in which the fourway valve mechanismheretoforereferred to directs the energizing fluid to tracking motor I5,this motor rotates shaft SI inlsuch manner as to carry with it the sungear5ll in desired direction. Spider l5 for ring gear 4I idles on shaft3|, moving freely relativethereto. Sungear 5E! meshes constantly withand rotates planet gears 44. These latter mesh with the inner teeth'43of ring gear 4I. Reacting against this ring gear when the latter islocked, they exert Vdriving impetus on power take-olf spider 45. In turnthisvapplies rotational effort to power take-off shaft 25. The manner inwhich the locking is` accomplished will now be described in conjunctionwith the following description of the slewing motor.

The slewing motor It is indicated generally at the bottom left of Figure2. Shaft 55 is powered by this motor, extending therethrough andincluding a stub shaft portion 5l at the, left side thereof. At itsouter end, this stubshaft portion 5l terminates in an enlarged brakinghead 53.

Motor I5 is carried by anti-friction bearings 59, provided in anintermediate casingl, made fast to block 28.- A further intermediatecasing member 6I separate from but Vfast-to casing 6l), serves to housesha-ft 51 in anti-friction'bearings 62. A sealing gasket 6 3 preventsleakage between casing 6I and the complemental portions 64, 65

lof an end cap indicated generally by the refereyes 69 provided indiaphragm'68.V This diaphragm is received in an opening 10 which isprovided by recesses in elements 65, 64. Normally it bears tightlyagainst the enlarged head 58 of shaft 51.

Through threaded orifice 1I in element 6,4, pressure iluid can beconducted from the exterior to the left side 18A of the space 18,provided by elements 64, 65. A fluid line 12 interconnects oriiice 1Iwith brake-release control I3 (Figure 1), while :a further fluid line 13connects this releast means I3 through T-connection 14 with the conduitmeans 15 leading from the outlet side of pump I6. Thus, th'e full outletpressure of pump I is exerted on diaphragm 68 to force it in brakingengagement against bearing plate 58. Shaft 55 extends throughanti-friction bearing i6 in block 28 outwardly to the right, andiscarried in turn, at its outer end, by roller or ball bearings 18, whicheffectively serve as thrust bearings. meshes with pinion 80 which isalso fast to th'e shaft 8l as is spur gear 82, This shaft is carried byblock 28. Spur gear 82 meshes with the outer teeth 4,2 on ring gear 4 I.Y

Energizing fluid is admitted to the slewing motor I6 through suitableports 83, 84 (Figure 4) either of which may serve as inlet or outletport, depending upon the direction in which the energizing fluid isdirected by` control unit I2 to the motor. Motor I6 may be of themulti-chambered rotary type, reversible in direction. As I have stated,preferably but not necessarily I use a motor available on the market.

In operation, just as has been stated, .the tracking motor starts theshaft 25 into rotation under high-torque, slow-speed con-ditions, inwhich case it is important that the ring gear 4I be held firmly againstrotation. As soon as starting inertia is overcome, it frequently isVdesirable to compound on the slow-speed characteristics of trackingmotor I5 and associated gear train the high-speed characteristics ofslewingmotor I6 and its associated gear train to bring the gun turret orother suitable load serviced by shaft ,25 as quickly as possible intoits approximate operable position. Then, when it is desired to bring theload smoothly and accurately to a predetermined stopping position,overcomingVA the inertia of motion,` recourse is again had to thetracking motor alone. first to brake motor'l positively againstmotiongthen quickly to release the same fully fromV the inhibitiveaction of such braking; and later, to brake motor I6 quickly to apositive stop, so that the ring gear 4I will again be locked.' Brakediaphragm 66 admirablyv fulfills these several functions, and givesquick,V positive, reliable'and efficient control at all times. v

When the motor I6 stands de-energized, a static headV of energizingfluid is established'at orice 1I on the 1eft side of VdiaphragmVtrundrer Spur gear 19 carried on shaft 55V Thus, it becomes necessary'substantially full line pressure from the outputj side of pumpll)(Figure 1); -The comparatively large area of this diaphragm insures thatthe' latter is forcedsharply to ,the right, in Figure 2, intoV brakingposition.V Similarly, the substantial contact area aorded by theenlarged head 58 of stub shaft 51 insuresthat positive braking action isavailable. Y Y

It is a characteristic of hydraulic equipment thatwh'en operating underload conditions, appreciable fluid leakage occurs between the movingparts. This leakage characteristic is availed of in the present instanceto insure quick and positive unseating o f` the diaphragm 68 from theshaft head 58 when pressure is removed from the left side of diaphragm68 by the brake release means I3. As soon as the motor I6 is broughtinto operation, reverse leakage pressure is exerted, which quicklyexerts suicient pressure against Ithe right side of diaphragm 68 toforce it away and to release it from the head 58 of shaft 51. Theabsence of static pressure head on` the left side of this diaphragm 68,occasioned by cut-off under Vcontrol valve I3, facilitates such action.The motor I 6 is then free to rotate without hindrance by the brake 68;Y

As soon as motor i5 is de-energized, however, the leakage pressure headwithin the motor is released by drainage occurring through opening inshaft 51, while simultaneously static pressure'head is again exerted atorice 1I. The large-area diaphragm V58 is again engaged firmly againstenlarged head 58, the resulting frictional resistance quickly andeffectively bringing the motor I 6 and its associated gear train to anabsolute stall, restraining the ring gear il against rotation. In thismanner, accurate and sensitive drive control is achieved for the powertake-0H shaft 25. The gun turret orY otherY suitable load can be quicklyand effectively positioned without overrunning of the turret or huntingof the motor unit II (Figure 1). y Discussion has already been had ofthe system in general and of the powering unit itself. There remainsfordescription, :the control unit l2V and the manner in which it exertseifective control over motors l5, I6. i

VUpon reference again to Figure l, unit I2 is seen to compriseYgenerallyja casing 86 in which are'housed a primary orifice 81, asecondary orice 88, a primaryload-controlled relief valve'88, and asecondary load-controlled relief valve 98. Cam shaft 28 serves toactuate the primary orifice members in a manner which will now bedescribed. This cam shaft V2() is powered either by a manual handle 2|,suitable automaticmeans.

n will beY recense that a constant direction, constant output isdeliveredat all times from the exhaust iluid Yis returned through.conduit to pump Ill. We will'assume, secondly,that handle 2 I is throwna slight distance Veitherway, outof Vits zero or rest position. CamfSBon shaft 28 thereupon lif'ts'cam follower rod 91soas to displace the`primary orifice memberl upwardly,

permitting thel flow vof f a Ymetered quantity 'of .Y

as shown, or throughV vaisance fluidirom conduit 'I5 through thisoriiioealong conduitwg, -to the right of orifice rnerriber-BI:`

A static pressure-head-is thereupon established in-.riser .99 Vwhich istied-inwithfconduit Alillythereby conductingl fluid-to 1the-to`p side ofprimary shunted directly back to the rservoir I4. A substantial part ofthe ilu-idcourses conduit 98. Blocked -at vsecondary-orifice` member 88;'which has not yet been affected by the movement of cam shaft 2l), thisfluid courses upwardly through riser Illl to the bottom side ofsecondary re-l,

lease valve 90. Thence the energizing fluid courses conduit II tofour-way valve I8 which controls the tracking motor. Through cam |02 andassociated cam follower I3, the direction of rotation of cam shaft 90has determined the direction of opening of four-way valve I8. We willassume that the direction of energization is as indicated by arrows inFigure l, so that line lull serves to conduct the energizing fluid fromfour-way valve I8 to port 23, now the admission port, of tracking motorI5. From port 2li, now the outlet port, the spent fluid returns throughconduit |05 to valve I8, and thence through riser IBG to associated lineS4 and thence back to reservoir I3.

Let us assume for the moment, however, that through control handle 2|,cam shaft 2li is rctated an equal extent in the opposite direction fromthat already described, `In such instance, the fluid through valve I 3courses line |65 to port 211, now the admission port of motor l5, andthence through exhaust port 23 and line I @il back to valve I8. Thecircuits between pump It and valve i8 remain as has already been traced.

We will assume that handle 2l has been swung still further in eitherdirection7 so that through cam IB'I and cam follower Ill, secondaryorifice element 88 is opened slightly.v Fluid then courses line 98,through element 88 and conduit m9 to four-way valve I9 for slewing motorI E, Through riser III) a static pressure head is exerted from conduit|09 on the top side of secondary relief valve 953, moving the piston953A thereof downwardly so as to block at least partly the intake portof line II. The quantity of fluid to tracking motor I5 is thusdiminished. Direct shortcircuiting of the output of pump Il) iseffectively precluded through the circuits already traced. The entireoutput of pump Il) thus is divided between the motors I5, I6. From thefour-way valve I9 the energizing fluid is directed to the slewing motorI 6. In the instance under discussion, rotation of handle ZI has been insuch direction as to cause iiuid to course conduit Iii from valve I t toport 83, now serving as the admission port of pump I6, Returning, thespent fluid courses through port 4, now serving as the outlet port,conduit II2, back to Valve I9, and thence through conduit IIB to conduit534 and back to reservoir Hl. Control of the four-way valve I 9 isaccomplished by means of cam I Id ggd follower rod II5, energized fromcam shaft Reversal of direction of rotation of handle 2i to the sameangular throw as has just been described results simply in reversal ofconnections between valve I9 and motor i6.

A cam SIS is provided on cam shaft 2d and actuates a cam follower II'Iwhich serves the brake release means I3, A static uid head ,is

' at` alltimes exerted ontheinletsideof-this brake releasemeans I3by-.suitablemeans such as `conduit 73 which ties inon the mainoutletlinel5 from` pump lil. The maximum line pressure is thus always availableatreleaseelement I3. The

design of the release-means I3is such that this member .isnormally..opensdthatl substantially full line pressure-from-linel13=isexerted through conduit 'F2 to orifice II .ofy slewing motor I6. Thisinsures that the brake diaphragm B8 (Figure 2) is forced fzzitnImaximum; line pressure .against the braking reaction element 58.;-ITheommon control meansZllforthe controlunit I2. and brake release unitI3, however, is so timed with element I3 and four-way Valve ISL-thatwhen thelatter is Aactuatedlto. energizesleWi-ngmotor I din. eitherdirection, immediate blocking is occasioned at release means I3.Thereupon, by the use of conventional bleeder means not shown, thepressure against diaphragm 68 is immediately released, and the motor ISis free to rotate, However, upon de-energization of four-way valve I bythrow of operating control handle ZI, the release means l 3 iscompletely unblocked, so that full line pressure is applied to conduit'I2 to return diaphragm (i8 to braking position against reaction plate53.

It will at once be evident from the foregoing that pump I0 operatesalways at maximum efficiency. Under accurate and sensitive control, iteffectively applies energizing Huid to either or both of two coactingmotors in such manner that these latter will service a variable andfluctuating load in the most eincent manner possible. The high-torque,low-speed motor I5, operating alone, serves always to service the loadwith maximum operating eiiiciency through its associated gear train.This is possible because the high-speed, low-torque motor I6 is at alltimes effectively blocked by brake 63 While it stands de-energized, sothat the ring gear 4I of the tracking motor gear system, with which thegear train of the slewing motor meshes, is effectively locked againstidling rotation on the system. Maximum reaction thrust is thus alwaysprovided for.

Inasmuch as the basic principles of my invention as herein disclosed aresusceptible to many constructional embodiments, and since manymodifications and adaptations may be made of the embodiment hereinbeforedescribed, it is to be understood that the foregoing description is,simply by way of illustration and is in no sense to be construed aslimitative.

I claim:

1. A hydraulic power unit comprising, in combination, a huid-energizedrotary motor having `an elongated shaft, a diaphragm disposed at one endof said shaft and normally bearing thereagainst and serving as a brake,means for supplying energizing fluid to said motor, iiuid means fornormally applying said diaphragm against the end of said shaft, meansfor releasing said brake, and a common control means for regulating saidiiuid supply means and said release means, and serving to actuate saidbrake release means as an incident to admittance of energizing fluid tosaid motor.

2- A hydraulic power assembly comprising, paired hydraulic motors havingpower output shafts, a source of fluid power supply for said motors,control valve means for metering fluid to said motors from said powersupply, a diaphragm disposed at the end of one of said motor shafts andserving as a brake for the same, means for releasing said brake, a powertake-off 11 shaft common to said motors, planetary gearing, connectingthe output shafts of said motors in driving relation with said take-011shaft, and control means for regulating said control valve means andserving to actuate said brake release means asi an incident toadmittance of energizing fluid to the motor corresponding to said brake.

ALBERT RIVINGTON STONE.

REFERENCES CITED UNITED ySTATES PATENTS Name Date Swanson Aug. 17, 1920Number v 1,349,924

Number Number l 12 y Name Date Robson May 7, 1929 Montelius Jan. 15,1935 Rosen Nov. 29, 1938 Verderber Apr. 11, 1939 Cannon Aug. 13, 1940Harrington Jan. 2, 1945 Linden et a1. Jan. 29, 1946 FOREIGN VPATENTSCountry Y Date Great Britain Apr. 19, 1911

